The invention relates to a synchronized and regulated power supply.
In order to maintain optimum performance of the television receiver, it is desirable to provide a regulated direct current potential (B+) to the various circuits of the receiver. Numerous types of regulated power supply circuits have been used to provide the desired regulation. One such type is a switching regulator power supply.
A switching regulator power supply is a very efficient type of regulated power supply since the switching device is alternately turned off and on and the regulation is accomplished by controlling the relative durations of the off condition and the on condition of the switching device.
In order to minimize the interference produced by switching of the switching regulator power supply, it is desirable to synchronize the switching with the synchronizing signals utilized to synchronize the deflection circuits. In addition to the synchronizing signals, the B+ level must be coupled to the switching device to provide feedback to control the B+ level.
In television receivers, where it is desirable to isolate the chassis from the alternating current potential source having an earthen ground reference to prevent electrical shock to the operator, the coupling of B+ and synchronizing signals to the switching device requires numerous components or complicated construction of an isolation transformer.
Also, television receivers utilizing line rate deflection systems of the type disclosed in U.S. Pat. No. 3,452,244 employing two bidirectional conducting switches require an input reactor between the source of B+ and the commutating bidirectional conducting switch to prevent short circuiting of the B+ during the commutating interval (i.e., when the commutating switch is turned on).